The present embodiments relate to real-time data and/or event management (RDEM) in a supervisory control and data acquisition (SCADA) system.
SCADA systems implement industrial processes or industrial control systems. For example, a SCADA system may monitor and control a manufacturing process using communications with sensors, actuators, and field devices (e.g., programmable logic controllers or remote terminal units). The SCADA system provides control capabilities and a user interface for interacting with the control and data acquisition of the process.
Various applications are performed by the SCADA system. A configuration application may be operated as a tool to tag or otherwise label field devices included in the controlled process. Business object applications may monitor progress of a part being manufactured or process being performed. Other application clients may include visualization applications, workflow monitoring, reporting, or communications applications.
The application clients rely on data from the field devices. Rather than requiring calls from different applications to the same field devices, the SCADA system implements real-time data and event management (RDEM). The RDEM implements a memory resident process image in which the states of the objects representing the physical process are kept valid and current in memory. When a change occurs, the change is received by field device gateways and routed to the RDEM for update. The application clients access the RDEM rather than performing calls to the field devices, allowing faster response and less communication load on the field devices. Critical process states which cannot be recovered following a system restart, so called retentive states, are also written to the persistence store during run-time. The RDEM may be configured by a configuration application. When the configuration is modified, the RDEM may write the new configuration to the persistence store.
The performance and reliability requirements of the RDEM make the RDEM one of the most complicated and costly components to develop and test in a SCADA system. Any change in the SCADA system requires extensive testing to make sure RDEM operates without loss of needed data. This often becomes the blocking point in bringing the SCADA system onto a new technology platform. If a new operating system or computing platform is available, the SCADA system is less likely to be upgraded due to the testing requirements.